Radiosignaling system



E. F. W. ALEXANDERSON.

RADIOSIGNALING SYSTEM.

APPLICATION FILED 050.24. 1918,

1,360,169. Patented Nov, 23, 1920.

inventor: Ern st F. .Alexanderson,

Hi 9 Attorney.

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UNITED ST PATENT OFFICE.

ERNST F. ALnXAnnnRsoN, or scnnnncrnnr, NEW roan, nssrenon TO GENERAL ELECTRIC COMPANY, a CORPORATION or NEW YORK.

RADIGSIGNALING SYSTEM.

Specification of Letters Patent.

Patented Nov. 23, 1920.

Application filed December 24, 1918. Serial No. 268,128.

To all whom it may concern. I

Be it known that 1, Elmer F. W. ALEX- ANDERSON, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Radiosigna'ling Systems, of which the following is a specification.

My present invention relates to radiosignaling systems and particularly to a method of adjusting a radiating system supplied with energy from an arc generator, to obtain a high degree of etliciency.

In my prior applications, Serial No. 123,276, filed October 2, 1916, and Serial No. 191,110, filed September 13, 1917, I have described and claimed a radiating antenna system which is of high efiioiency by reason of the fact that a plurality of ground connections for the aerial are provided with a tuning coil in each ground connection. The antenna described in the aforesaid applications is supplied with energy from a high frequency alternator and, when the various tuning coils are properly adjusted to obtain the most efiicient combination of alternator and antenna, acts in efl ect as a plurality of substantially independent radiators. In this case, the entire energy from the alternator is supplied to one of these radiators and this radiator in turn supplies energy to the other radiators.

By reason of this method of operation the feed resistance of the antenna or the apparent resistance of the circuit which is fed by the alternator as determined from the energy output and the current supplied to the first radiator, is much greater than when the antenna system is operated as a.

single radiator. For example, in the case of one long horizontal antenna to wh1ch my prior invention has been applied, the feed resistance when operating as a single r'adi ator was'3.6 ohms and when six ground connections with tuning coils were provided so that the antenna operated as six substantially independent radiators, thefeed resistance increased to about 20 ohms. This increaseof feed resistance'does not affect the etficientoperation of the system when a high frequency alternator is used as a source of energy. In case, however, it is desired to use an arc generator as a source of supply a difierent situation is presented. The characteristics of the are are such that it will operate most efilciently and deliver its maximum output with a given value of resistance in the circuit to which it supplies energy. 'This resistance may be from two to four ohms. In the case above mentioned then the arc generator might deliver its maximum output when a single ground connection was employed and the antenna acted as a single radiator. As i have pointed out, however, in my co-pending applications mentioned above, the antenna when supplied with a given amount of energy will operate most eiiioiently when it is adjusted to act as a plurality of substantially independent radiators. Hence it appears that it the arc is to deliver its maximum output the advantages of multiple tuning must be sacrificed while if all of the advantage of multiple tuning is to be obtained the arc output and efficiency will be greatly reduced. In practice a compromise between these two extremes will be found .to produce the maximum strength of sigtotal of the charging currents inthe ditferent ground connections is a maximum. The charging current in the ground connection supplied by the arc will then be greater than that in the other ground connections but may be less than'it would be if the other connections were omitted. The total of all of the charging currents, however, will be greater than the current which would be supplied by the arc if only one ground connection were employed, although the total output of the arc will be less. The feed resistance of the circuit supplied by the arc will be greater than it would be if a single ground connection were used but will be less than it would be'if the antenna were adjusted'to obtain the full advantage of multiple-tuning with a high frequency alter nator. In effect the antenna will act in part as a single radiator and in part as a plurality of substantially independent radiators. Part of the energy will be supplied to the antenna in the same manner as when a single ground connection is used and part will be supplied at high'voltage from the first independent radiator to the other sections of the antenna which act as independent radiators in the same manner as when the full advantage of multiple tuning is obtained.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims, the invention itself, however, both as to its organization and method of operation, together with furtherobjects and advantages thereof, will best be understood by reference to the following description taken in connection with the accompanying drawing in which I have illustrated diagrammatically one way in which my invention may be carried into effect.

In the drawing I have indicated an antenna of the horizontal type and comprising a plurality of wires 1, supported by the usual towers 2. Ateach of these supporting towers I provide grounding connections .8 containing tuning coils 4, 5 and 6. The are generator which is indicated at 7 and which is supplied with current from the usual direct current source Sis placed in the first of these ground connections. This arc generator may consist of any well known form of arc device which is adapted to produce high frequency oscillations. which are provided at the other points are in the form of capacity grounds Qronsisting ofa network of wires supported a short distance above the ground. The capacity ground is used in this case to prevent the short circuiting of the direct current genorator 8 which supplies energy to the are 7.

In the operation of this system to obtain the maximum radiation the adjustment of tuning coils 4, 5 and 6 is varied and the charging currents in theydifferent connections observed until an adjustment is arrived at where the total of the different charging currents becomes a maximum. When this condition is reached the system will operate at its greatest efficiency as a re diator since the amount of energy radiated is proportional to the sum of the separate charging currents. i

In the system which is illustrated and described in the co-pending applications above mentioned, the various tuning coils are .ordinarily so adjusted that the charging currents in all of'the ground connections are substantially equal. Under these conditions the effective inductance in the tuning coils will be of such'valueas to neutralize the capacity of that portion of the aerial which is adjacent the ground connections in which the individual tuning coils are inserted. With this adjustment the antenna as here shown would operate as three substantially The grounds independent radiators. hen the arc gel 'erator is employed as a source of energy,

sistance of the circuit to which the ar supplying its energy may be much greater than the resistance at which the arc operates to give its maximum output. As a result it will be found that when the system is adjusted, as described above, to secure maximum value of the total charging current. that the charging current through the tn ing coil l will be greater than that through coils 5 and 6. This indicates that the inductance of the coils 5 and 6 is not great enough to neutralize entirely the capacity of those sections of the aerial which are adja'cent to the ground connections of these coils and which would naturally be fed through these ground connections. This means that the inductance of the coil 4 must be of such value that it will neutralize the capacity of the section of the aerial-adj'acent to its ground connection and will also neutralize a portion of the capacity of those sections whichare supplied through the coils 5 and 6. While the actual operation of the antenna under these conditions may be somewhat complex, it may be assumed for all practical purposes that the antenna is operating in part as a single radiator and in part as a plurality off-substantially in dependent radiators. A portion of theenergy supplied by the arc will be furnished to the antennain the same manneras though the antenna were acting as a single radiator. That section of the antenna which is adjacent the first ground connection will also act as an oscillation transformer and a portion of the energy will be supplied" to the other sections of the antenna from this first portion at a high voltage.

In the adjustment of the system such as that which I have described in which a plural'ity of ground connections with tuning coils therein are employed, it may be found desirable, in order to obtain the most favorable value of the feed resistance, to disconnect entirely one or more of the ground connections nearest the connection through which energy is applied :to the antenna. In the claims which follow, therefore, where I refer'to an adjustment of the tuning coils, I mean to include the actual disconnection of one or more of these coils. 7

While I have illustrated'a single embodiment of my invention, it willbeapparent that it is not limited -to the particular form of antenna indicated or to the particular arrangement of ground connections indicated, but that it may be applied to any desired form of antenna inwhich a plurality of ground connections with tuning coils therein are provided.

What I claim as new and desire to secure by Letters Patent of the United States, is:

l. The method of obtaining a desired value of feed resistance in an antenna having a plurality of grounding connections with tuning coils therein, and having means for introducing the energy through one of the ground connections which consists in neutralizing a portion only of the distributed capacity of the antenna adjacent each ground connection by means of the tuning coils therein and neutralizing the remainder of the distributed capacity of the antenna by means of the tuning coil in the connection through which the energy is introduced to the antenna.

2. The method of operating ,a radiating system comprising an antenna having a plurality of grounding connections with tuning coils therein which consists in adjusting the tuning coils in such a way that the charging currents in the different ground connections are unequal and the antenna acts in part as a single radiator and in part as a plurality of substantially independent radiators.

3. The method of operating a radiating system comprising an antenna having a plurality of grounding connections with tuning coils therein and supplied with energy by an arc generator which consists in varying the adjustment of the different tuning coils until a point is reached at which one of the ground connections carries a greater charging current than the others and the sum of the charging currents in the individual ground connections becomes a maximum.

4. The method of operating a radiating system comprising an antenna having a plurality of grounding connections with tuning coils therein and supplied with energy by an arc generator which consists in adjusting the feed resistance of the circuit to which energy is supplied by the generator to a value at which the sum of the charging currents in the individual ground connections becomes a maximum by varying the values of the charging currents in the difl'erent ground connections'so that the charging currents in difl'erent ground connections have different values.

5. The combination in a radiating system of an antenna having a plurality of grounding connections with tuning coils therein and an arc generator for supplying high frequency energyto said radiating system, said tuning coils being so adjusted that the charging currents in different ground connections will have difierent values and the feed resistance of the circuit to which energy is supplied having such a value that the sum of the charging currents produced in the individual ground connections is a maximum.

6. The combination in a radiating system of an antenna having a plurality of grounding connections with tuning coils therein and an arc generator connected to one of said ground connections for supplying energy to said antenna, said tuning coils being so adjusted that the charging current in the ground connection through which energy is supplied is of different value than that in the other ground connections and the sum of the charging currents in the individual ground connections isa maximum.

7. The combination in a radiating sys tem of an antenna having a plurality of grounding connections with tuning coils therein and an arc generator for supplying high frequency energy to said radiating system through one of said grounding connections, said tuning coils being so adjusted that the charging current through the ground connection through which-energy is supplied will be greater than the charging currents in the other ground connections and the antenna will act in part as a single radiator and in part as a plurality of substantially independent radiators.

8. The combination in a radiating system of an antenna having a plurality of grounding connections with tuning coils therein and having means for introducing the energy through one of the ground connec tions, each of said tuning coils in the other ground connections being so proportioned as to neutralize a portion only of the distributed capacity of the antenna adjacent its ground connection and the tuning coil in the ground connection through which energy is supplied having such a value as to neutralize the remainder of the distributed capacity of the antenna.

In witness whereof I have hereunto set my hand this 23rd day of December, 1918.

ERNST F. W. ALEXANDERSON. 

